Download (PDF 443 KB): https://research.fs.usda.gov/download/treesearch/26171.pdf
Abstract
Sudden oak death has emerged as a major threat to the oak forests of California. In oaks and tanoak, this disease complex consists of a previously unreported fungus-like pathogen,
Phytophthora ramorum, insects (bark and ambrosia beetles), and a secondary fungus,
Hypoxylon thouarsianum. Species monitored in this study were coast live oak (
Quercus agrifolia), California black oak (
Q. kelloggii), and tanoak (
Lithocarpus densiflorus). Disease progression plots were initiated in March 2000 to determine infection and mortality levels, symptomology, and changes in disease status. Plots were placed in two ecologically different sites in Marin County, China Camp State Park and a protected watershed of the Marin Municipal Water District (MMWD). Ten plots of 0.1 to 0.2 ha, selected to encompass the range of habitat types and species compositions found within these forests, were placed in each site. For all oaks and tanoaks, the following data were recorded quarterly for one year: diameter (dbh); presence/absence and abundance of seeps; presence/absence of
H. thouarsianum fruiting bodies; presence/absence of bark and ambrosia beetles; and condition of the foliage. More than 750 oaks and tanoaks in these plots have been permanently tagged and geolocated using a global positioning system (GPS). Across China Camp State Park, independent and unbiased estimates of infection and mortality levels were acquired in summer 2001 using point-centered quarter sampling.
Parent Publication
Citation
McPherson, Brice A.; Wood, David L.; Storer, Andrew J.; Kelly, Nina Maggi; Standiford, Richard B. 2002. Sudden oak death: disease trends in Marin county plots after one year. In: Standiford, Richard B., et al, tech. editor. Proceedings of the Fifth Symposium on Oak Woodlands: Oaks in California''s Challenging Landscape. Gen. Tech. Rep. PSW-GTR-184, Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture: 751-764
